Hiawatha Trail

Another "rails to trails": mountain bike trail along the old Milwaukee Road railroad grade. It starts just over the continental divide in Montana; by the time you exit the ~1.3 mile tunnel at the start, you're in Idaho. (This photo is a bit beyond the Idaho portal of the tunnel.) You can then get a shuttle ride back to the trailhead so you don't have to pedal back uphill! The trail overall is about 15 miles.
"Hiawatha" is the name of the Native American protagonist in Longfellow's eponymous poem, who was supposed to be so swift he could outrun his own arrows. His name was applied to the Milwaukee Road's express passenger service, presumably to emphasize its speed!